In some examples, a graph processing server is communicatively linked to a shared memory. The shared memory may also be accessible to a different graph processing server. The graph processing server may compute an updated vertex value for a graph portion handled by the graph processing server and flush the updated vertex value to the shared memory, for retrieval by the different graph processing server. The graph processing server may also notify the different graph processing server indicating that the updated vertex value has been flushed to the shared memory.